The goal of this study was to reveal the chromosome evolution of Trilliaceae. Trilliaceae is an angiosperm family widely distributed in Eurasia and North America. All species of this family carry giant chromosomes, the mean size of which is about 9 milliards base pairs, that is three times more that the total length of human genome. In general, chromosome sets of Trilliaceae are conservative (.x = 5 in all species) but previous studies have revealed high interspecies variability of heterochromatin banding patterns within the family. We have studied the Q, CMA and AgNOR chromosome banding patterns of Paris incompleta, Trillium recurvatum, T. erectum, T. grandiflorum and compared their chromosome maps with the earlier studied Q- and CMA-banding patterns of Daiswa hajnanensis, P. quadrifolia, Trillium tschonoskii and T. camschatcense Then, to determine phylogenetic relationships between species, we compare p-distance between Trilliaceae species through ITS1-5.8S-ITS2 sequence analysis. The ITS1-5.8S rDNA-ITS2 of Trillium tschonoskii, T. camschatcense, P. incompleta, P. quadrifolia were sequenced and analyzed. It was shown that a characteristic feature of the Q-banding pattern of all Paris sensu stricto species is multiple small AT-rich heterochromatic bands. On the other hand, there are large both AT-enriched and GC-enriched heterochromatic bands on a part chromosomes of the Daiswa karyotype. The chromosomes of all Trillium species, with except of T. tschonoskii carry large AT-enriched heterochromatic bands. Our results of nuclear genome ITS1 and ITS2 sequences analysis support the position of T. tschonoskii on the branch of Paris species in spite of both morphology analysis and chloroplast gene matK sequence of this species are clustered T. tschonoskii with T. camschatcense.